There are currently five known human aspartic proteases, namely, pepsin, gastricsin, cathespin D, cathespin E and renin, and these have widely varying functions. Pepsin and gastricsin are involved in nutritive processes in the stomach, cathepsin D is involved in protein turnover in many cell types, and renin has the highly specific function of angiotensin production from its precursor form, angiotensinogen. The precise role of cathepsin E remains to be confirmed, although its location in some epithelial cells types has indicated a role in antigen processing. It may also be involved in certain inflammatory conditions, such as Helicobacter pylori infection in the stomach. This indicates that the Aspartic Proteinase family has an established, proven history as therapeutic targets. Clearly there is a need for identification and characterization of further members of Aspartic Proteinase family which can play a role in preventing, ameliorating or correcting dysfunctions or diseases, including, but not limited to, Alzheimer's Disease, cancer, and prohormone processing.